These phenomenons are more specific to the Americas, affecting both the Northern and Southern hemispheres. There are many factors that add up for either of these events to happen, such as wind speeds and how they push the Pacific Ocean currents. The most reported effects that the phenomena have shown are the rise and fall of ocean temperatures and the severity of natural disasters, such as the recent hurricanes we have seen hit the southern U.S. and the extreme rise in tornados across Tornado Alley. 

When El Niño happens, weak western winds are unable to push ocean water westward in and around the Pacific Ocean. Because of these strong winds, pacific water temperatures begin to rise one degree Fahrenheit at a time, which can create an ideal stew for hurricane formation. Due to the weak winds, northern Americans experience warmer conditions and a drier climate. For us here in the Midwest, there has been an uptick in tornados since El Niño started a couple of years ago. One example is the EF-0 tornado that swept through the north shore in early September, leaving fallen trees and many people in Glencoe, Deerfield, and Highland Park without power for days on end. As of Sept. 18, The Center for Disaster Philanthropy reported over 1,400 tornados across the country, but mainly in Tornado Alley.

With La Niña on the other hand, rough western winds are able to push the Pacific Ocean waters west and eastward, causing the spaces left behind to fill up with colder water, dropping the temperatures. We experience a cooler and wetter climate in the more northern part of the United States. These two events normally happen between a 2-7 year period, the time it normally takes for one of these phenomena to stir up. This time around, though, it has been six years since the last switch between El Niño and La Niña. The strange thing is that La Niña events are rare, so although we have been in El Niño for the past couple of years, it might not be long until we see one again. 

What we can expect from the switch here in the North Shore is a much colder winter than we have been experiencing the past couple of years. Since the climate will be colder and wetter, we can expect more snow this winter. The good news is that the snow will stick to the ground this time instead of immediately melting away like it has the past few winters.